Here's a strange issue that popped up with Tiger:
I bring my PB to work sometimes and connect it to the network here. I can't access network drives or anything like that, but the Mac OS is smart enough to get an internet connection for browsing and instant messaging.
After an upgrade to Tiger last weekend, I can still connect to the internet and use a web browser, but when I attempt to login to AIM via iChat or Adium, it times out. Is there a setting or something I can change to get it to connect again?